first off, omg she is GORGEOUS! Those eyes! I love her!
second off - is that a German short haired pointer? I had one growing up, his name was taylor. Sadly he was only with us for about 7 years before he developed brain cancer

I LOVED that dog and that breed is just awesome!
third - you dont really know how big a pup will get ever or when they will stop growing. I think the breeder just sounded like she was willing to work with you if you REALLY wanted another pup that fit the 'standard' for breeding. Its kind of out of her hands as to how big your pup will get. Oh yeah, my boys were 6.2lbs and 4.2lbs when they were 15 months old. Both within the standard, but by 18months old they were 8.5lbs and 5.5lbs. So they both had a growth spurt late and no breeder would have been able to predict that!
I think its so nice to hear that you are willing to accept that you won't be able to breed her and are more than ok with that. She will offer you so much joy in so many ways!